package top.ddandang.blog.utils;

import org.apache.tomcat.util.codec.binary.Base64;
import org.springframework.stereotype.Component;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

/**
 * <p>
 *AES 加密解密工具类
 * </p>
 *
 * @author D
 * @version 1.0
 * @date 2020/6/6 7:46
 */
@Component
public class AesEncryptUtil {
    /**
     * 使用AES-128-CBC加密模式，key需要为16位,key和iv可以相同！
     */
    private final String KEY = "dDanDangDDanDang";

    private final String IV = "dDanDangDDanDang";


    /**
     * 加密方法
     *
     * @param data 要加密的数据
     * @param key  加密key
     * @param iv   加密iv
     * @return 加密的结果
     */
    public String encrypt(String data, String key, String iv) {
        try {
            //"算法/模式/补码方式"NoPadding PkcsPadding
            Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");
            int blockSize = cipher.getBlockSize();

            byte[] dataBytes = data.getBytes();
            int plaintextLength = dataBytes.length;
            if (plaintextLength % blockSize != 0) {
                plaintextLength = plaintextLength + (blockSize - (plaintextLength % blockSize));
            }

            byte[] plaintext = new byte[plaintextLength];
            System.arraycopy(dataBytes, 0, plaintext, 0, dataBytes.length);

            SecretKeySpec keyspec = new SecretKeySpec(key.getBytes(), "AES");
            IvParameterSpec ivspec = new IvParameterSpec(iv.getBytes());

            cipher.init(Cipher.ENCRYPT_MODE, keyspec, ivspec);
            byte[] encrypted = cipher.doFinal(plaintext);

            return new Base64().encodeToString(encrypted);

        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * 解密方法
     *
     * @param data 要解密的数据
     * @param key  解密key
     * @param iv   解密iv
     * @return 解密的结果
     */
    public String desEncrypt(String data, String key, String iv) {
        try {
            byte[] encrypted1 = new Base64().decode(data);

            Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding");
            SecretKeySpec keyspec = new SecretKeySpec(key.getBytes(), "AES");
            IvParameterSpec ivspec = new IvParameterSpec(iv.getBytes());

            cipher.init(Cipher.DECRYPT_MODE, keyspec, ivspec);

            byte[] original = cipher.doFinal(encrypted1);
            return new String(original);
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * 使用默认的key和iv加密
     *
     * @param data 加密数据
     * @return 加密结果
     */
    public String encrypt(String data) {
        return encrypt(data, KEY, IV);
    }

    /**
     * 使用默认的key和iv解密
     *
     * @param data 解密的数据
     * @return 解密结果
     */
    public String desEncrypt(String data) {
        return desEncrypt(data, KEY, IV);
    }
}